1. Field of the Invention
The present invention generally relates to hand-operated fastener applying devices and specifically to spring-powered staplers.
2. Description of the Related Art
Various spring-powered staplers employs basically the same operating principle that is to use a spring to store energy, which is then released to drive a blade to expel a staple out of the bottom of the stapler. The stapler of the present invention also uses this operating principle, but makes the structure more simplified, compact and flexible.
U.S. Pat. No. 2,326,540 issued to Krantz discloses a staple gun in which a hand lever is pivoted at the back and an actuating lever engages a vertically positioned spring and driving assembly, hence Krantz's staple gun is quite bulky.
U.S. Pat. No. 2,671,215 issued to Abrams discloses a staple gun with similar vertically placed spring and driving assembly, but a different actuating means.
U.S. Pat. No. 2,769,174 issued to Libert discloses a staple gun in which an actuating means employs two linked levers and spring and driving member assembly vertically positioned.
U.S. Pat. No. 3,862,712 issued to LaPointe et al. discloses a staple gun with a staple feeding track that slides rearward to expose a staple loading chamber. A releasable latch assembly retains the track in position.
U.S. Pat. No. 4,119,258 issued to Ewig, Jr. discloses a staple gun with a body and hand lever constructed substantially of plastic material. Its hand lever is pivoted in the front and its spring and driving assembly is vertically positioned.
U.S. Pat. No. 5,988,478 issued to Marks discloses a stapling machine in which an actuating level is used to store energy in the power spring and then released it to force a plunger to move downward and expel a staple from the bottom of the stapling machine. In order to accommodate the actuating lever, the hand-operated stapling machine is less compact.
U.S. Pat. No. 6,918,525 issued to Marks discloses a desktop stapler in which a spring lifting level is also used to activate the stapler, hence it is less compact.